Shareholders' Equity - Preferred Stock Issued and Outstanding (Details) - USD ($) $ in Thousands		9 Months Ended
	Mar. 02, 2021	Sep. 30, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Preferred stock, issued (in shares)		10,300,000	10,000,000
Preferred stock, outstanding (in shares)		10,300,000	10,000,000
Preferred stock, liquidation preference		$ 550,000	$ 250,000
Preferred Stock, Series A
Class of Stock [Line Items]
Preferred stock, issued (in shares)		10,000,000	10,000,000
Preferred stock, outstanding (in shares)		10,000,000	10,000,000
Preferred stock, liquidation preference		$ 250,000	$ 250,000
Preferred stock, dividend rate		6.15%
Preferred Stock, Series A | LIBOR
Class of Stock [Line Items]
Preferred stock, dividend rate, basis spread		3.65%
Preferred Stock, Series B
Class of Stock [Line Items]
Preferred stock, issued (in shares)		300,000
Preferred stock, outstanding (in shares)		300,000
Preferred stock, liquidation preference		$ 300,000
Preferred stock, dividend rate	4.65%	4.65%
Preferred Stock, Series B | US Treasury (UST) Interest Rate
Class of Stock [Line Items]
Preferred stock, dividend rate, basis spread	4.076%	4.076%